Tardive dyskinesia (TD) is an involuntary movement disorder associated with the use of neuroleptic medications. Although the disorder has become relatively common among psychiatric patients maintained on neuroleptics, there is currently no clear understanding of its pathophysiology and no specific treatment approach. Thus, the longterm objectives of this application are: (1) to understand the etiology and natural history of TD; and (2) to prevent and/or control its occurrence. The specific aims of the proposed research are: (1) to identify demographic, neuropsychological, medical and psychosocial risk and prognostic factors for TD among chronic neuroleptic users; (2) to assess current methods for factors for TD among chronic neuroleptic users; (2) to assess current methods for defining and classifying cases of TD; (3) to describe the longitudinal course of TD; (4) to estimate the frequency and duration of TD in one clinical setting; and (5) to examine the related processes of TD case finding and referral in that clinical setting. The proposed research includes three interrelated studies of TD involving different designs but conducted within a single source population - the outpatient division of the Connecticut Mental Health Center in New Haven. The incidence study is a prospective follow-up investigation of outpatients maintained on neuroleptics, who are free of dyskinetic movements at intake and who have never been diagnosed with TD. Approximately 400 patients at risk will enter the study over a 2-year intake period and will be followed for as much as 3 to 5 years using semi-annual exams to assess the level of abnormal movements and to record current medications. The focus of this study will be to address specific aims 1 and 4. In contrast to the only other major incidence study of TD in this country, this population is racially mixed, low income group, most of whom have been maintained on neuroleptics for many years. The prognostic study includes 228 patients diagnosed with TD at the TD Clinic at CMHC and followed retrospectively after diagnosis, using TD Clinic records of regularly scheduled quarterly visits. The prevalence study includes cross-sectional data collected from 189 outpatients who participated in the program at CMHC between July 1982 and February 1983 and who were being maintained on neuroleptic medications. The focus of this study is to address specific aims 4 and 5 with secondary emphasis on aim 1.